ButtonTheme 按钮样式

可容纳一个孩子，为后代的按钮指定默认样式。常用于多个相同按钮的样式统一，避免一一设置。

相关组件

MaterialButton FlatButton RaisedButton OutlineButton

ButtonTheme使用

   <br />属性参数同MaterialButton，可以通过ButtonTheme.of获取按钮主题数据，"<br />也可以为ButtonTheme【后代】的按钮组件设置默认样式，包括颜色、形状、尺寸等。<br />![214.gif](https://cdn.nlark.com/yuque/0/2020/gif/326147/1589512135014-4a699b3b-228c-4a63-ab46-649b9193bb93.gif#align=left&display=inline&height=60&margin=%5Bobject%20Object%5D&name=214.gif&originHeight=60&originWidth=262&size=71105&status=done&style=none&width=262)

import 'package:flutter/material.dart';
class ButtonThemeDemo extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return ButtonTheme(
      buttonColor: Colors.orange,
      splashColor: Colors.blue,
      minWidth: 40,
      shape: CircleBorder(
        side: BorderSide(width: 2.0, color: Color(0xFFFFDFDFDF)),
      ),
      child: Wrap(
        spacing: 10,
        children: <Widget>[
          RaisedButton(onPressed: (){},child: Icon(Icons.add)),
          FlatButton(onPressed: (){},child: Icon(Icons.add)),
          OutlineButton(onPressed: (){},child: Icon(Icons.add)),
          MaterialButton(onPressed: (){},child: Icon(Icons.add)),
        ],
      ),
    );
  }
}